Identifying the voltage level of a transmission line

The voltage levels of transmission lines in Finland are 110, 220 and 400 kilovolts (kV). One kilovolt is 1,000 volts (V). The voltage level can be recognised by the length of the insulator string and the number of insulator elements.

Voltage level of transmission line

Length of insulator string

Number of insulator discs

110 kV

approx. 1 metre

6-8

220 kV

approx. 2 metres

10-12

400 kV

approx. 4 metres

18-21



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